Tetsuo Saito

is a Japanese politician who served as chief representative of the Komeito from 2024 to 2026. He served as Minister of Land, Infrastructure, Transport and Tourism from 2021 to 2024 and Minister of the Environment from 2008 to 2009.

Born in Shimane Prefecture, he was educated at the Tokyo Institute of Technology and worked as an engineer before entering politics. He was elected to serve as chief representative of the Komeito to succeed Keiichi Ishii, who was defeated in the 2024 election.

Career

Tetsuo Saito was born on 5 February 1952, in Ōchi District, Shimane. His father was a village councilman belonging to the Liberal Democratic Party and the head of a local group supporting Noboru Takeshita.

Saito attended the Tokyo Institute of Technology as an undergraduate studying applied physics, graduating in 1976, and received a Ph.D. in engineering from the same school. His first employment was with the major construction firm Shimizu Corporation. Saito was a visiting researcher at Princeton University for three years beginning in 1986. He was elected to the Diet for the first time in 1993.

Saito was appointed Minister of the Environment by Prime Minister Yasuo Fukuda on 1 August 2008. In the Cabinet of Prime Minister Tarō Asō, appointed on 24 September 2008, Saito was retained in his post.

On 9 November 2024, Saito was selected as leader of Komeito following an extraordinary party convention to replace Keiichi Ishii, who lost his parliamentary seat in the 2024 Japanese general election.

On 10 October 2025, Saito announced that it would leave the ruling coalition, over disagreements with new LDP president Sanae Takaichi.

On 15 January 2026, Yoshihiko Noda and Saito announced that the Constitutional Democratic Party and Komeito would merge in the lower-house to form a new centrist party named the Centrist Reform Alliance. In the 2026 general election, the CRA collapsed to just 49 seats; following the election, Noda and Saito resigned as party co-presidents.

After the Diet convened, Saito was made chairman of the Committee on Discipline in the House of Representatives.

Personal life His main hobbies are swimming and trains.